Measure UN thread with metric mic?????

[Bruce Caulley]

Ahoy!

 

I have a 1.625" 12UN OD thread to measure and I only have metric thread mics. The pitch works out to 2.117mm so I have zero'd up 2mm-3mm anvils.

 

My questions are: What is the effective diameter of a 1.625" 12UN thread, and can I use the metric mic to measure it?????

 

thanks

 

Bruce

[Guest]

not sure if this is what you want but the minor dia. is 1.52276,pitch dia is 1.57087 wire size is .04811 and meas over wires is 1.64303 all in inches

[LEV]

I think you can measure it with metric mic. Is it 2A or 3A type of thread?

[connormac]

oops I didn't read Del. I thought thread wires also.

[LEV]

for 2A ouside dia should be between 41.229mm/40.94mm & pitch dia between 39.855mm/39.705mm, minor dia 38.71mm max.

 

for 3A ouside dia should be between 41.275mm/40.985mm & pitch dia between 39.9mm/39.789mm, minor dia 38.755mm max.

[Bruce Caulley]

Thanks fellas. The mic reads ok and the OD is in spec with full form inserts, so all appears to be good. Never mic'd an imperial thread with a metric mic so I was a little worried that I was setting myself up for a fall.

 

Bruce